1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device having electrostatic discharge (ESD) protection functionality, and more particularly, to a liquid crystal display device having ESD protection functionality for lighting modules based on ESD protection mechanism installed in the LCD panel of the LCD device.
2. Description of the Prior Art
Because liquid crystal display (LCD) devices are characterized by thin appearance, low power consumption, and low radiation, LCD devices have been widely applied in various electronic products for panel displaying. In general, the LCD device comprises liquid crystal cells encapsulated by two substrates and a lighting module for providing a light source. The operation of an LCD device is featured by varying voltage drops between opposite sides of the liquid crystal cells for twisting the angles of the liquid crystal molecules of the liquid crystal cells so that the transparency of the liquid crystal cells can be controlled for illustrating images with the aid of the lighting module.
FIG. 1 is a schematic diagram showing a prior-art liquid crystal display device. As shown in FIG. 1, the liquid crystal display device 100 comprises an LCD panel 110 and a flexible printed circuit board 150. The LCD panel 110 comprises a gate driver 125, a source driver 135, a first electrostatic discharge (ESD) protection unit 120, and a second electrostatic discharge protection unit 130. Disposed on the flexible printed circuit board 150 are a lighting module 160, a third electrostatic discharge protection unit 170, and a fourth electrostatic discharge protection unit 180. The first electrostatic discharge protection unit 120 is coupled to the gate driver 125 for protecting the gate driver 125 from being damaged by ESD events. The second electrostatic discharge protection unit 130 is coupled to the source driver 135 for protecting the source driver 135 from being damaged by ESD events. The third electrostatic discharge protection unit 170 and the fourth electrostatic discharge unit 180 are coupled to opposite sides of the lighting module 160 for protecting the lighting module 160 from being damaged by ESD events.
FIG. 2 is a schematic diagram showing another prior-art liquid crystal display device. As shown in FIG. 2, the liquid crystal display device 200 comprises an LCD panel 210 and a flexible printed circuit board 250. The LCD panel 210 comprises a gate driver 225, a source driver 235, a first electrostatic discharge protection unit 220, and a second electrostatic discharge protection unit 230. Disposed on the flexible printed circuit board 250 are a lighting module 260 and a third electrostatic discharge protection unit 270. The ESD protection mechanism of the LCD panel 210 is identical to the ESD protection mechanism of the LCD panel 110 shown in FIG. 1. Two ends of the third electrostatic discharge protection unit 270 are coupled to opposite sides of the lighting module 260 for protecting the lighting module 260 from being damaged by ESD events.
It is noted that the electrostatic discharge protection units for protecting the lighting module in the aforementioned prior-art liquid crystal display device are disposed on the flexible printed circuit board as shown in FIG. 1 and FIG. 2. In general, the lighting module comprises a plurality of lighting units, and consequently there are several electrostatic discharge protection units disposed on the flexible printed circuit board for protecting the plurality of lighting units from being damaged by ESD events. That is, the plurality of lighting units in conjunction with corresponding electrostatic discharge protection units are required to put into the layout of the flexible printed circuit board. Accordingly, extra circuits of the corresponding electrostatic discharge protection units complicate the layout and fabrication of the flexible printed circuit board. Also, extra layout areas of the flexible printed circuit board are required to accommodate the extra circuits of the corresponding electrostatic discharge protection units.